The present invention relates to a method of manufacturing duckbill valves, and more particularly to a method of splitting such valves.
Duckbill valves are non-return valves which have a generally tubular body portion, from which two opposed lips extend. The opposed lips contact each other at the ends away from the tubular body. When the fluid pressure at the tubular end of the valve exceeds that outside the lips, the opposed lips open, allowing fluid to flow forwards through the valve. When the fluid pressure is greater outside the lips than inside the tubular body, the lips are pressed tightly in contact with one another, by the fluid pressure, and so prevent fluid from flowing backwards through the valve.
Cross-linked polymer duckbill valves are formed by compression transfer moulding and the polymer is cross-linked in the mould with the opposed lips integrally formed with each other, being joined by a land. The cross linking of the polymer results in an excessive cycle time.